A protective relay operates by continuously monitoring electrical parameters, detecting abnormalities, making decisions, and triggering circuit breakers to isolate faulty sections. This process helps protect equipment, maintain power system stability, and ensure safety for. Protective relays are used in industrial power generation and supply systems to open and isolate branch circuits in the case of excessive current. They are activated by means which are not dependent on a continual AC supply. Three fundamental components required for each circuit breaker. In overcurrent. Relay protection is the discipline of designing schemes that detect faults, coordinate relays, and isolate equipment without outages.